As a transfer belt for use in electrophotographic image forming apparatus, materials having durability and high strength such as polyimide and polyamideimide are known.
However, such thermoplastic resin belts have poor strength. A transfer belt formed of polyimide has creep and elongation resistance, but has a fragile end needing a reinforcing tape, resulting in problems of productivity and cost.
Japanese published unexamined application No. 2006-150896 and Japanese Patent No. 3821600 disclose a method of irradiating an electron beam to a resin endless belt after melted, extruded and molded for the purpose of increasing strength thereof.
This is common with the present invention in irradiating an electron beam.
However, this method continuously extrudes a belt without distinguishing an end from the other parts and irradiates an electron beam to the whole surface of the belt, resulting in the fragile end of the belt having improved elasticity.
Japanese Patent No. 3821600 discloses a method of applying a reinforcing tape along an edge of an outer surface of the belt. Japanese published unexamined application No. 2005-62822 discloses a transfer belt including a polymer alloy binder formed of an anti-crack polyester polyether elastomer for improving toner adherence in the first transfer and polybutyleneterephthalate more flexible than PET resins for ensuring toner transferability in the second transfer, and an electroconductive material dispersed therein. However, it is recommended that an end reinforcing tape is used, and which does not mean the belt end has sufficient strength.
Because of these reasons, a need exist for a belt-shaped member having an unbreakable end.